Azathioprine
Azathioprine is a type of drug known as a disease-modifying
anti-rheumatic drug, or DMARD. These drugs have the effect of
dampening down the underlying disease process, rather than simply
treating symptoms. Azathioprine reduces the activity of the immune
system (the body’s own defence system), so it is always used with
care.
Why is azathioprine prescribed?
Azathioprine is used in the treatment
of several different types of rheumatic disease, including
rheumatoid arthritis and systemic lupus erythematosus (SLE).
Doctors may prescribe it for people on
steroid treatment so that their steroid dose can be reduced.
When and how do I take azathioprine?
Azathioprine is taken in tablet form
either once or twice a day, with or after food.
Your doctor will advise you about the
correct dose. Usually you will start on a low dose (e.g. 50 mg per
day) and your doctor may increase this if necessary. The dose you
are given will depend on your body weight.
How long does azathioprine take to work?
Azathioprine does not work immediately. It may be 6–12 weeks
before you notice any benefit.
What are the possible risks or side-effects?
Azathioprine can cause nausea (feeling sick), vomiting,
diarrhoea, skin rashes, loss of appetite or hair loss. Taking
azathioprine can make you more likely to develop infections, and
azathioprine can affect the liver. You should tell your doctor or
rheumatology nurse specialist straight away if you develop any of
the following after starting azathioprine:
- a sore throat
- a fever
- any other symptoms of infection
- unexplained bruising or bleeding
- jaundice (eyes or skin turning yellow)
- any other new symptoms or anything else that concerns you.
You should stop azathioprine and see your doctor immediately
if:
- any of the symptoms listed above are severe
- you have not had chickenpox and you come into contact with
someone who has chickenpox or shingles
- you develop chickenpox or shingles
Chickenpox and shingles can be severe in people on treatments
such as azathioprine which affect the immune system. Therefore you
may need antiviral treatment, which your doctor will be able to
prescribe.
There is a slightly increased risk of certain types of cancer
with azathioprine. Discuss this with your doctor.
What other treatments could be used instead of
azathioprine?
A number of other drugs are used in the treatment of rheumatoid
arthritis and related conditions. Your doctor will
discuss these other options with you.
Will I need any special checks while on azathioprine?
Because azathioprine can affect the blood count (one of the
effects is that fewer blood cells are made) and can sometimes cause
liver problems, your doctor will arrange for you to have a blood
test before you start treatment and then regular blood checks while
on azathioprine. This is very important. You may be asked to keep a
record booklet with your blood test results, and you should bring
this with you when you visit your GP or the hospital. You
must not take azathioprine unless you are having regular
checks.
Can I take other medicines along with azathioprine?
Azathioprine may be prescribed along with other drugs in
treating your condition. Some drugs interact with azathioprine
(e.g. allopurinol, used in the treatment of gout), so you should
discuss any new medications with your doctor before starting them,
and you should always tell any other doctor treating you that you
are on azathioprine.
Azathioprine is not a painkiller. If you are already on a
non-steroidal anti-inflammatory drug (NSAID) or painkillers you can
carry on taking these as well as azathioprine, unless your doctor
advises otherwise.
Do not take over-the-counter preparations or herbal remedies
without discussing this first with your doctor, rheumatology nurse
or pharmacist.
What about immunisations?
If you are on azathioprine it is recommended that you should not
be immunised with ‘live’ vaccines such as yellow fever. However, in
certain situations a live vaccine may be necessary (for example
rubella immunisation in women of childbearing age), in which case
your doctor will discuss the possible risks and benefits of the
immunisation with you.
Pneumovax (which gives protection against the commonest cause of
pneumonia) and yearly flu vaccines are safe and recommended.
Can I drink alcohol while on azathioprine?
If you drink alcohol you should only drink it in moderation
because azathioprine can affect the liver.
Does azathioprine affect fertility or pregnancy?
You should not normally take azathioprine when pregnant. If you
are planning a family or become pregnant while taking azathioprine,
you should discuss this with your doctor as soon as possible.
What about breastfeeding?
You should not breastfeed if you on azathioprine. The drug may
pass into the breast milk and could be harmful to your baby.
Where can I obtain further information?
If you would like any further information about azathioprine, or
if you have any concerns about your treatment, you should discuss
this with your doctor, rheumatology nurse or pharmacist.
Remember to keep all medicines out of reach of
children.
PLEASE NOTE: We have made every effort to
ensure that this content is correct at time of publication, but
remember that information about drugs may change.
This page is for general education only and does not
list all the uses and side-effects associated with this
drug. For full details please see the drug information
leaflet that comes with your medicine. Your doctor will assess your
medical circumstances and draw your attention to any information or
side-effects that may be relevant in your particular case.
Our drug information is revised
annually and published at the start of the year.